| In this study, the dynamic changes of grass growth characteristics, soil physicochemical properties and their correlations used eight alpine grass species (Puccinellia distans (PD), Neotrinia splendens (NS), Leymus chinensis (LC), Lolium perenne (LP), Festuca rubra (FR), Elymus nutans (EN), Poa pratensis (PP), and Puccinellia tenuiflora (PT)) of mainly promoted in grassland restoration on the Qinghai-Tibet Plateau were planted for three years, and the grey correlation degree was used to comprehensively evaluate the saline-alkali tolerance of the eight grass species were investigated by field investigation and laboratory studies. The aims were to select suitable and adaptable pioneer grass species for planting in Qaidam basin saline-alkali soil. The results showed that under saline-alkali stress, the coverage and aboveground biomass of NS, LP, and PP were 63.00%, 60.75%, 58.50%, and 16.05 g·m-2, 16.50 g·m-2, 10.05 g·m-2, respectively, significantly higher than other species (P<0.05). NS has the highest soil initial gravimetric water content, which is 11.16%, significantly higher than PD, LC, FR, EN and PT (P<0.05). The soil saturated water-holding capacity, capillary capacity and field capacity of NS and LP were 28.63%, 27.09%, 26.53% and 27.98%, 26.61%, 26.01%, respectively, significantly higher than other species (P<0.05). NS and LP have relatively high soil noncapillary porosity and capillary porosity with 2.32%, 39.18% and 2.00%, 41.51%, respectively; NS has the lowest soil bulk density and pH, which were 1.18 g·cm-3 and 8.53, respectively. FR has the highest soil organic matter content, which was 11.04 g·kg-1; The soil available nitrogen content of PD, LC and FR were 38.90 mg·kg-1, 39.85 mg·kg-1, 39.00 mg·kg-1, respectively, significantly higher than other species (P<0.05); The soil available phosphorus content and available potassium content of LC were 19.73 mg·kg-1 and 398.98 mg·kg-1, respectively, significantly higher than other species (P<0.05). Linear regression analysis showed a highly significant correlation between aboveground biomass of grasses and soil physical properties and available nutrient content. Redundancy analysis showed that soil noncapillary porosity, capillary capacity and capillary porosity were the most significant factors affecting growth characteristics of eight alpine grasses (P<0.05), the interpretation rates were 72.30%, 4.30% and 2.50%, respectively. The synthetic evaluation results of grey correlation degree indicate that NS, LP, PP and EN is have excellent performance and were more suitable for promotion and planting in saline-alkali soil of the Qaidam Basin. |